Figure 1

Schematic representation of the rFsh and rLh treatment applied to flathead grey mullet females (n = 21). The protocol was applied according to the development of female gonads determined by ovarian biopsies. Weekly doses of 6, 9 and 12 µg kg⁻¹ rFsh were applied to induce previtellogenesis (~ 100 µm oocyte diameter) to vitellogenesis (> 200 µm) and vitellogenic growth was maintained with a dose of 12 µg kg⁻¹ per week. When the mean diameter of the largest oocytes was ≥ 300 µm, in addition to rFsh, rLh was administered in increasing doses. Initially an rLh dose of 2.5 µg kg⁻¹ was given and maintained until females presented ≥ 400 µm oocytes and was raised to 4 and 6 μg kg⁻¹. At ~ 500 µm diameter, weekly rFsh doses were reduced to 4 μg kg⁻¹ whereas rLh was increased to 9 μg kg⁻¹. A combination of 4 μg kg⁻¹ rFsh and 12 μg kg⁻¹ rLh per week were administered until vitellogenic growth was completed (~ 600 µm). Each point corresponds to a weekly administration. This scheme represents the longest pattern of administration of those females that required a total of thirteen weeks to complete vitellogenic growth.